The instant invention relates to fastening devices and more particularly to a device which is manually depressible for automatically driving tacks and the like.
Several types of impacting devices have been heretofore available for driving tacks and other fastening elements. In this regard, the U.S. Pat. Nos. Reynolds, 1,601,324; Graffious, 1,824,399; Cullen, 2,212,339; Wheeler, 2,346,884; Binns, 2,481,190; Sitz, 2,774,133; Lazar, 2,907,241; Hammell, 2,962,807; Wright, 4,150,774; and Okuda, 4,312,472 disclose a variety of devices of this general type and represent the closest prior art to the subject invention of which the applicant is aware. In this connection, all of the above patents relate to devices wherein spring elements are manually loaded and then released to effect impacting actions with hammer elements to drive tacks or other fastening elements. The device of the instant invention also operates in this same general manner, but it differs substantially from the devices disclosed in the above patents, both in its operation and in its impacting mechanism. In particular, the device of the instant invention is operative in a simple procedure wherein an end of the device is urged forwardly against a tack to load a hammer element and a drive spring until the hammer element and the drive spring reach a fully loaded position whereupon the hammer element is automatically released by a release pin and propelled into impacting engagement with the plunger to drive the tack. Many of the previously known devices have not been automatically actuatable, and they have required separate elements for loading and unloading the drive springs thereof; and hence they have been substantially more complicated, both structurally and operatively, than the device of the instant invention. Furthermore, the operative components of the tack driving device of the subject invention cooperate in a unique and simple manner to provide substantial advantages over all of the heretofore known devices of this general type.
The device of the instant invention generally comprises a housing, a plunger which is slidably mounted in the housing so that it is longitudinally movable therein between an outwardly extended first position and a retracted second position, a hammer element mounted in the housing, and a drive spring mounted in the housing for biasing the hammer element toward the inner end of the plunger. The hammer element is releasably connected to the plunger by a release pin which maintains the hammer element in axially spaced relation to the inner end of the plunger as it is moved inwardly into the housing from its outwardly extended first position so that the hammer element is urged against the drive spring to effect a loading thereof. However, the release pin is operative so that when the plunger reaches its retracted second position, the hammer element is released from interconnection with the plunger, and the hammer element is propelled into impacting engagement with the inner end of the plunger. Accordingly, by positioning the outer end of the plunger in engagement with the head of a tack or the like, and pushing the housing forwardly so that the plunger is urged towards its retracted second position, the spring and the hammer element are urged into loaded or cocked positions; and finally, when the plunger reaches its retracted second position, the hammer element is released so that it impacts the inner end of the plunger. Further, the impact between the hammer element and the plunger is transmitted to the head of a tack or the like through the plunger so that a driving force is applied to the tack or the like.
Accordingly, it is a primary object of the instant invention to provide a simple, relatively small and easily manipulatable automatic device for driving tacks and other fastening elements.
Another object of the instant invention is to provide a tack driving device wherein a spring is automatically loaded and then released to cause a hammer element to be propelled into impacting engagment with a plunger for driving a tack or the like.